The present invention relates to a device for holding two structural parts in a spaced relationship to each other which has a spacer for filling the space between the two structural parts, the spacer having a support part which can be brought into a position fixed in rotation with respect to the first structural part and a drive part which is displaceable axially with respect to the support part by rotation, the support part and the drive part resting against each other on a helical engagement surface which has an inclination which is opposite to the inclination of a thread of a screw which, when screwed into an axial opening in the drive part, carries the latter along with it.
From EP-A1 0 176 663 a device of this type is known which has a support part which can be brought into a position fixed in rotation with respect to the first structural part. The helical engagement surface of the drive part rests on a helical engagement surface of said,support part. The support part and the drive part lie one behind the other in axial direction, a screw which passes centrally through the two parts having a thread opposite that of the engagement surface. In the case of a right-hand screw, the engagement surface is developed as a left-hand thread. Accordingly, upon the screwing-in of the screw the screw moves the rotary drive part along by frictional lock of its external thread in the opening in the rotary drive part, so that the two engagement surfaces slide on each other and the end surface of the rotary drive part strikes against the second structural part, together with the fact that the distance between the two structural parts is filled up. Further screwing-in of the screw then no longer leads to a driving of the rotary drive part, so that the screw can be screwed in all the way and enters, on the opposite side, into a corresponding internal thread of the second structural part, as a result of which the two structural parts are attached to each other.